READINGTON — Mayor Julia Allen told a large crowd at a public hearing on a Solberg Airport ordinance that she doesn’t understand why the two sides can’t reach an agreement. After all, she said, they share a “common goal.”

They don’t.

Mayor Allen and others in Readington Township have battled for years to seize control of the Solberg Family’s sizable land holdings, through the purchase and/or condemnation of development rights or the land itself.

The mayor’s not alone in failing to understand why the Solbergs don’t want the $21.7 million the township is offering. So rumors circulate that the Solbergs want to expand and turn their small general aviation airport, which opened in 1941, into a jetport for Boeing 747s.

Others rumors accuse the family of holding out for the highest bid from a residential developer.

Ask Thor Solberg about jets and he’ll tell you that they’ve been landing here since 1989.

Are jumbo airliners next? He’s likely to shake his head ruefully, suggesting that there are apparently more reasons why that won’t happen than hours in the day.

The township has pursued the development rights and/or the Solbergs’ 726 acres for at least 15 years. But residential developers have knocked long and hard at landowners’ doors for many decades. Super-sized developments started gobbling up the countryside in the 1980s in Hunterdon.

If the Solbergs wanted to sell, they had ample opportunity.

Mayor Allen has said that small, general aviation airports are under the same type of pressure to sell as the family farm, because the land in New Jersey is worth more than the operation it’s supporting. That’s true at those properties where owners have failed to change their business plans over time.

The once-diversified family farm — a manageable herd of cows, chickens to fill a large coop, a dozen pigs and land to grow crops to feed livestock and people — has given way to specialized or niche farms.

One farmer may cut hundreds of acres of hay each year to sell throughout the winter to horse farms. The next farm over may specialize in direct-to-consumer organic vegetables. Wholesale nursery stock is grown on some land. Dairy farms still sell milk in bulk, and now often expand into artisanal cheeses.

Careers that complement — farm machinery sales — or augment farm income allow others to keep the family land because they’ve afforded a steady income, health insurance benefits and a pension.

Solberg Airport adapted by welcoming hot-air balloons when they surged in popularity. It derives income hosting the largest balloon and music festival in North America, the N.J. QuickChek Festival of Ballooning. When the weather is warm the Horizon Blue Cross Blue Shield blimp and other blimps fly from Solberg.

Land in many of these families is an heirloom. It carries much greater monetary value than a centuries-old grandfather clock or engagement ring passed down through time, but is similarly rooted in personal histories.

The sentimental attachment to land on which generations have toiled, grown strong and been nourished can’t be underestimated.

That can be particularly true in families that remember the ancestor who immigrated here in search of a better life or to escape a repressive government, such as those short on search-and-seizure laws.

Mayor Allen has spent countless hours over the years, with little or no remuneration, helping families who needed or wanted to sell their development rights in order to keep their land.

Had every landowner taken that route in the 1970s through the early 2000s, other taxpayers in New Jersey could never have kept up with the cost of preservation.

Hunterdon really remains green through a combination of public and private resources. There’s nothing wrong with a landowner saying, “I don’t have to sell and I don’t want to sell.”

There’s also nothing wrong with elected officials seeking an agreement to offer protection against development, such as a “right of first refusal” should a landowner’s fortunes, or ancestors, change the game.

But condemnation? By its very definition that’s not a common goal between seller and buyer.